Portable refrigerating apparatus



Sept. 16, 1952 J. B; MAXWELL 2,610,472

PORTABLE REFRIGERATING APPARATUS Filed Oct. 1948 v 2 SHEETSL-SHEET 1 mvsu'ron JOHN'BIFFTEL MAXWHL A "JMW J. B. MAXWELL PORTABLE REFRIGERATING APPARATUS Sept. 16, 1952 $I-IEETS-4SHEET 2 Filed Oct. 1, 1948 M a. R M I W mM mQm/m mm a 6 W, J 0

v ofexample in;

, hgwnin Figure 5,;

Patented Sept. 16, 1 952 BURTABLE REFRlGERATlNQ APPARATUS John Bertel Maxwell, Vancouven -fBritish Comm: 1! a j bia, Canada, assignor to Maxwell Refr gq c Limi eatV ncw r, ri sh CQ H bi C a 1 Applicationfictober1,1948,-SerialN0.52,239"? I InCanada June 13,1946 3 v i J .7

This invention relates to" improvements in refrigerating apparatus; a r

This application is a continuation-in-part of the applicants pending application Serial Number 779,003,.f1led October 10, l947,'now aban-- doned.

An object of the present invention is the provision of refrigerating apparatus in which solldi fled. carbon dioxide or similar refrigerant may be used to'keep commodities for relatively lon periods.

outfreezing them solid.

With the above and other objects in present invention consists essentially of refrigcrating apparatus comprising a storage compartment, a chest forfireceiving carbon" dioxide or" similar refrigerant'acoil in the compartment communicating at'its inner end with the chest,"

and a pressure maintaining valve in the coil adjacent the outer end thereof, said valve being adapted; to discharge into the atmosphere out side the; compartment, as more fully described'in the following specification and illustrated by way the accompanying drawings, 'in

which:

Figure l isa, perspective view of a simple form' of refrigerating apparatus,

Figure 2 is a horizontal longitudinal section throughthe apparatus shown in Figure 1,

vFigure; 3' is a 'vertical longitudinal section through Figure 1, f V

.Figure 4 is a vertical cross section through vth apparatus adjacent one end thereof, I

Figure; 5 V is a; vertical longitudinal sectionthrough analternative formgof the apparatus,.

7 tion for a comparatively object is. the provision of refrig' crating apparatus in-whlch solidifiedcarbon dioxide maybe used 'to' keep'products cool with view, the

ii.- adiagrammatic view of thesystem 5 .I' 1.11

, 2 claims. (01.16242 any convenient manner.

means of a perforated grill it which 'is spaced,

Referring more particularly to Figures l to 4 of the drawings, the refrigerating apparatus is in the form of a container [0 which is divided into'a storagecompartment Hand achest l2.

.. All the walls of the container are insulated, as

shown, and an insulated wall [3 separates the chest I? from the compartment 1 I. A gas chamher 15 provided at the bottom of the-chest in above thebottom of the gas chamber. Actually, this grill divides the chest into two sections. An insulated cover [8, see Figure 1, is provided for the compartment maria an insulated cover I9 is provided for the'che'st. This chest is adapted to receive blocks 20 of solidifld carbon dioxide or similar refrigerant. These blocks rest on the grill I6. 'If desiredfa floating cov'er 2|, may beprovided in the chest. This cover slidably fits in th'efchest and rests upon the top of the blocks 20 so that th 'area in which these blocks are located graduallydecreasesas the blocks diminish in size. A refrigerating coil is mounted in the compartment H, communicating at its inner end with the chest and at its outerfend with the atmospheregoutside the compartment; This coil winds' backand forth along. awall of the comp'artment. The innerend' of this coil may communicatewiththe chest in any convenient manner, but it'is preferable to have the gas chamber 15 and this inner end communicat with the chest through said chamber. Thus, the coil preferably communicates With-thebottom of the refrigerant chest.

A pressure maintaining valvesi located in the coil adjacent-the outer end thereof, and said valve-is-adapted to discharge. into the atmosphere outside the compartment. One'form of pressure maintaining valve'is illustrated in Figure 2, and consists 'ofone or more sections of pipe of re- "ducd diame'ter, this figure showing sections28 and; 29. "The diameter-of the section 2B is less than that of the coil 25, whilethe diameter of the section 29 is less than that of the section 28. When a plurality of pipe sections are used in this type of valve, the diameters of the sections progressively become less towards the atmosphere outside the compartment; In the illustrated setup, the section 29 may discharge di-' -rectly-outof the compartment, oras shown, it

"may discharge into a section of pipe 30,,which is. of the same diameter asthe coil 25,.said sectionfill, discharging .outzof the compartment. It isrref red, althou h not solute y-n w a y. to haveanother @113 in the st ra e;

This may be' done "by.

partment. The inner end of this coil communicates with the refrigerant chest in the same manner as the inner end of the coil 25. Thus, in this form of the invention, the inner end of the coil communicates with the gas. chamber IS. The outer end of the coil communicates with the atmosphere outside thecompartment H ',,and a .control valve 35' is located in this" coilladja-cent its outer end. This valve may be inside or outside the compartment, and is preferably in form of amanual shut-off valve.

Normally, the valve 35 is closed. The blocks 20' of the refrigerant are continuously: giving cite: gas at a very low temperature: Thls gas l'scol lected in the chamber l5, and" asits pressure builds up, it flows through the'coil-rli Thaprese 4 gas chamber l5, and thence through one or both of the coils in the storage compartment.

Figures 5 and 6 show an alternative of this invention which is preferred for relatively large storage areas. It may be used either in cold storage buildings, or in railroad refrigerator cars. In this. alternative; 4'5 is a; relatively largestorage compartment in'which is mounted a'refrigerant chest 46 having a removable cover 41. The walls ofithis chest may or may not be insulated. It is preferable, to provide a gas chamber 48 at the bottom of the chest, said chamber being separated therefrom by: aperforated grill 49. The chest is sure maintaining valve in this coil keepszthezpxesesure therein at a predetermined point. As the diameters of the pipe sections 28 and 29 areprogressively smaller than that of the coil, the flow of gas is restricted atthis point. Inother' words, thegas from the refrigerant-blocks: accumulates faster than'it' is able to pass through the sections. 2 8 and2-9' of= the pressure maintainingzvalve; This keeps the gas in the coil zli within the compartment' for a predetermined time-in order thatitwill absorb the maximum amount ofheat' fromsaid compartment; This-controlling ot the flowof" gas prevents theztemperat-ureinthe compart' ment from going too lovw andiit prevents-:there' frigerant blocks from": disappearing too: rapidly. At the same time, lay-maintaining a continuous now, of the gas; it is preventedfromtreacliing a pressure which: would in' itselff create? heat and M thus reduce its lieateabsorbing capabilities;

Themain purpose of'thetcoili'fl tozgivea" better. control: of" the temperature: in the, compartement. H. For example; when; the container is" first. charged with.a.refifi'gerant; it may be. desir able .quicklyito, lower the temperature, in the; stone age; department-to a desiredipoint'. This maybe done.by opening, the.-.valve; 35. to, permit a flow :of' gas through the. coil 3141. Onceth'ej desired." temperature is reached, the.vaivemaybeclesedl The coilmay nowbe. able. td'keep theco'mpartrnent. at this point. However,, if it. isldesirednto lbwer thetemperature-in the compartment .lielow. that; normall-y maintained bythe, coil. 25, the valve. y be. opened toaccomplish. this. Thelower.

temperature. may be; maintained; lay, leaving, the;

valve slightly open; in whiehcaseitacts as apres sure maintaining valveinv the; same. manner a the one inthe coil 25. g

With this: arrangement, the. commoditiesstobe cooled may be: kept inthe; compartment.- l Irwithout; danger of. freezing. Ifiil]: is, desired quickly to. freeze some; article itmay. be" placedomthezfioah ing: cover 2 lin. the: chest. I'2r; Thetarticle wi'll; be; kept in a frozen stateas long asit remainswingthe chestand. as longt as there'sis anxysolidisrefri'gerantr therein. If .;desired,.ai:sectiorrt 3310f? thezinsulation I of: thepartitiorr l-3smayx betremovablei; Ifithissin sulation; section removed", the; tempera-lame the compartment; U. will? drop sharply and; will. remaimbelow freezing; point until: .the*:insulationsectiorris returned to. itsipositionsinzthe. partition; Asuwillbaseen the? above; this-apparatus;

is designed? toim'ake thenni'm'ost use. of the; gases: given: oif 'b'y thelrefrigerant:blocks:. This is helpedvv by: providing. the. floating. cover. 2 L1 so: that. the:

effective area of the chest in which thBsblOlCkS. area located remains-just: large enough? to accommos date the :bloclc s. Thus; theses"; cannot-accumulatih the-chest; tut-must move-down lntei'tfili with a non-return check valve: 52:.1. Aheadenpipel 54-connects the: inner ends of theacoil's: to. a, pipe 55: which, in; turns connected: to; one;' on more; outlet pipes, such as pipes: 5.6" and 5 -1, whicliextend to the gas chamber. valve 60 is: located. in; the; pipe 55:: This valvezis designedwoopen when: the pressure in. the; chest; and-gas chamber reaches a pnedeterminedrpomt;

and it closesv when this pressure. dropsl belciwsaid It has been found that the best results:

point. areobtainedwhen Lthisva'lve is. settoropemwhen the? gas: pressure; l the chest; reaches somewl'lere.

from -Mto 1 8% pounds.

Each-coil? Fill-preferablyhas: a; non retiirrr'. checks valve 63 adjacent its outer end, and these outer. ends: are connected; to a.;common; discharge, pipe 64;; which. communicates: with the, atmosphere; outside the compartment-.45.- Aiblows-dowmvalve 6 6; is-located in this dischargepipebetweerr the coilsand-theatmosphere; Thisvalveisdesigned' to open when: the: pressure: in; the: coils; neachesv'a:

certain. point, and. to close-again ,wherr the; press.

sure drops; to another predetermined: point. It:

has been found desirable to have this valve: open when the. pressure-reaches stimewheretrronriil; to

l0= pounds andf to. havetit: 'jclosedaga-irrxwhen; thu pressure-- drops. to approximately half; the. open ing pressure, that is, in thissexamplegeate on Pounds. V f

I des e t 8; drain p pe. Hi; having: control: cock: H; maybe provided a for: removineiany: moisture:- whiclr-mayaccumulaterinthesysteim This drain: pipe; extend. from. the pipe 51 outside; the: compartment, Itisalso: preferable toprovideia valve: 'H= to: th'erpipe said piper withering a;

safety valyer'lfl: therein whichwi-saadapted: toiopeniw in: the-eventzofithe 'pressurerin: the system rising 'to a'dangerous pointz. 2 Wherrthechest: lfiris:charged:with.carbon diox ide blocks, the gas given 01f accumulates ill'lth'li tained when the pressure in thefc'hest' iskept-- A pressure controli right pressure for obtaining the maximum results from the refrigerant. Experiments have proven that considerably higher pressures tend to reduce the efliciency of the gas as a refrigerant. With this arrangement, it usually takes some time to build up the required pressure in the coils after the pressure therein has been reduced to the minimum point by the blow-down valve. Ihis keeps the gas in the coils long enough to absorb a maximum amount of heat. If the gas moves too rapidly through the coils, it is wasted. On the other hand, if it is kept too long or if the pressure is too high, its efficiency is considerably decreased.

The number of coils in the compartment 45 depends upon the minimum temperature which is desired to obtain in this compartment. One coil only may be used if the minimum temperature is not too low. However, for relatively low points it is desirable to use two or more coils rather than one comparatively long coil. It seems that if the coil is too long the gas is subjected to too much friction therein and its eificiency is greatly reduced. I An advantage of the multiple coils is that the compartment 45 may be used to store commodities at different temperatures. For instance, if a very low temperature is desired, all four coils may beused. If, on the other hand the required temperature is not very low, the valves 5| of one or more coils may be closed to cut off their respective coils from the chest. The remaining coil or coils will then keep the temperature at the desired point. The check valves 63 will prevent any of the gas getting back into the shut off coils from the common discharge pipe 64. This coil arrangement is particularly valuable when the apparatus is used in refrigerator cars. The car may be used to transport a product, such as fish, in a frozen state, and on the return trip it may be used to carry another product, such as fruit, which should be just chilled and not frozen.

It is obvious that both forms of this invention may be used for air conditioning purposes.

The storage compartment may be a room or area in which the temperature is to be maintained at a desired point. The cooling coils may be located in the room or in the walls thereof. Furthermore, air may be cooled in the storage compartmen and then blown into the room or area. This apparatus is particularly useful in air-conditioning railway coaches and sleepers. In view of the above, the terms "storage compartmen or compartment as used in this specification and the accompanying claims, is intended to include rooms, areas, auditoriums, and the like.

What I claim as my invention is:

1. Refrigerating apparatus comprising a storage compartment, a chest for receiving solid carbon dioxide or similar refrigerant, a gas chamber communicating with the bottomof the chest, at least two outlet pipes from the gas chamber, a common pipe from said outlet pipes, a pressure control valve in the common pipe, said valve opening when the pressure in the chest reaches a predetermined point and closing when it drops below said point, a plurality of individual coils in the compartment communicating at their inner ends with the outlet pipe on the side of the control valve remote from the chest, a valve in each coil adjacent the inner end thereof by means of which its coil may be shut off from the chest, a common discharge pipe connected to the coils and communicating with the atmosphere outside the compartment, and a blow-down valve in the discharge pipe, said valve being adapted to open when the pressure in the coils reaches a predetermined point and to close again after the pressure has dropped to another predetermined point.

2. Refrigerating apparatus comprising a storage compartment, a chest for receiving solid carbon dioxide or similar refrigerant, a coil in the compartment communicating at its inner end with the chest and at its outer end with the atmosphere outside the compartment, a pressure control valve in the coil adjacent its inner end, said valve opening when the pressure in the chest reaches approximately 14 to 18 pounds and. closing when it drops below said point, and a blowdown valve in the coil adjacent its outer end, said blow-down valve being adapted to open when the pressure in the coil reaches approximately from 8 to 10 pounds and to close again after the pressure has dropped to approximately 4 or 5 pounds.

JOHN BERTEL MAXWELL.

REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,878,042 Wagner Sept. 20, 1932 1,888,646 Weston Nov. 22, 1932 1,893,483 Belt Jan. 10, 1933 1,949,518 Vold Mar. 6, 1934 1,951,074 Warren Mar. 13, 1934 1,951,679 Sherrick Mar. 20, 1934 2,039,334 Nagy May 5, 1936 2,056,731 Lith'gow Oct. 6, 1936 2,089,965 Justheim Aug. 17, 1947 FOREIGN PATENTS Number Country Date 522,507 Great Britain June 19, 1940 

